to be honest i take very little selenium, as I noticed it makes me depressed. I cut out the selenium altogether and felt great for a month. but then i think i started to get a little hyperthyroid so cut back a lot of Iodine for 4-5 days and have been eating 1-2 brazil nuts daily. ill start back at 100mgs tomorrow.
I suggest you look at lowering your selenium to 100 mgs a day or two days. see how you feel.